xref: /xnu-12377.61.12/osfmk/mach/vm_prot.h (revision 4d495c6e23c53686cf65f45067f79024cf5dcee8)
1 /*
2  * Copyright (c) 2000-2021 Apple Computer, Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 /*
29  * @OSF_COPYRIGHT@
30  */
31 /*
32  * Mach Operating System
33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
34  * All Rights Reserved.
35  *
36  * Permission to use, copy, modify and distribute this software and its
37  * documentation is hereby granted, provided that both the copyright
38  * notice and this permission notice appear in all copies of the
39  * software, derivative works or modified versions, and any portions
40  * thereof, and that both notices appear in supporting documentation.
41  *
42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45  *
46  * Carnegie Mellon requests users of this software to return to
47  *
48  *  Software Distribution Coordinator  or  [email protected]
49  *  School of Computer Science
50  *  Carnegie Mellon University
51  *  Pittsburgh PA 15213-3890
52  *
53  * any improvements or extensions that they make and grant Carnegie Mellon
54  * the rights to redistribute these changes.
55  */
56 /*
57  */
58 /*
59  *	File:	mach/vm_prot.h
60  *	Author:	Avadis Tevanian, Jr., Michael Wayne Young
61  *
62  *	Virtual memory protection definitions.
63  *
64  */
65 
66 #ifndef _MACH_VM_PROT_H_
67 #define _MACH_VM_PROT_H_
68 
69 /*
70  *	Types defined:
71  *
72  *	vm_prot_t		VM protection values.
73  */
74 
75 typedef int             vm_prot_t;
76 
77 /*
78  *	Protection values, defined as bits within the vm_prot_t type
79  *
80  *  When making a new VM_PROT_*, update tests vm_parameter_validation_[user|kern]
81  *  and their expected results; they deliberately call VM functions with invalid
82  *  vm_prot values and you may be turning one of those invalid protections valid.
83  */
84 
85 #define VM_PROT_NONE    ((vm_prot_t) 0x00)
86 
87 #define VM_PROT_READ    ((vm_prot_t) 0x01)      /* read permission */
88 #define VM_PROT_WRITE   ((vm_prot_t) 0x02)      /* write permission */
89 #define VM_PROT_EXECUTE ((vm_prot_t) 0x04)      /* execute permission */
90 
91 /*
92  *	The default protection for newly-created virtual memory
93  */
94 
95 #define VM_PROT_DEFAULT (VM_PROT_READ|VM_PROT_WRITE)
96 
97 /*
98  *	The maximum privileges possible, for parameter checking.
99  */
100 
101 #define VM_PROT_ALL     (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
102 
103 /*
104  *	An invalid protection value.
105  *	Used only by memory_object_lock_request to indicate no change
106  *	to page locks.  Using -1 here is a bad idea because it
107  *	looks like VM_PROT_ALL and then some.
108  */
109 
110 #define VM_PROT_NO_CHANGE_LEGACY       ((vm_prot_t) 0x08)
111 #define VM_PROT_NO_CHANGE              ((vm_prot_t) 0x01000000)
112 
113 /*
114  *      When a caller finds that he cannot obtain write permission on a
115  *      mapped entry, the following flag can be used.  The entry will
116  *      be made "needs copy" effectively copying the object (using COW),
117  *      and write permission will be added to the maximum protections
118  *      for the associated entry.
119  */
120 
121 #define VM_PROT_COPY            ((vm_prot_t) 0x10)
122 
123 
124 /*
125  *	Another invalid protection value.
126  *	Used only by memory_object_data_request upon an object
127  *	which has specified a copy_call copy strategy. It is used
128  *	when the kernel wants a page belonging to a copy of the
129  *	object, and is only asking the object as a result of
130  *	following a shadow chain. This solves the race between pages
131  *	being pushed up by the memory manager and the kernel
132  *	walking down the shadow chain.
133  */
134 
135 #define VM_PROT_WANTS_COPY      ((vm_prot_t) 0x10)
136 
137 #ifdef PRIVATE
138 /*
139  *	The caller wants this memory region treated as if it had a valid
140  *	code signature.
141  */
142 
143 #define VM_PROT_TRUSTED         ((vm_prot_t) 0x20)
144 #endif /* PRIVATE */
145 
146 /*
147  *      Another invalid protection value.
148  *	Indicates that the other protection bits are to be applied as a mask
149  *	against the actual protection bits of the map entry.
150  */
151 #define VM_PROT_IS_MASK         ((vm_prot_t) 0x40)
152 
153 /*
154  * Another invalid protection value to support execute-only protection.
155  * VM_PROT_STRIP_READ is a special marker that tells mprotect to not
156  * set VM_PROT_READ. We have to do it this way because existing code
157  * expects the system to set VM_PROT_READ if VM_PROT_EXECUTE is set.
158  * VM_PROT_EXECUTE_ONLY is just a convenience value to indicate that
159  * the memory should be executable and explicitly not readable. It will
160  * be ignored on platforms that do not support this type of protection.
161  */
162 #define VM_PROT_STRIP_READ              ((vm_prot_t) 0x80)
163 #define VM_PROT_EXECUTE_ONLY    (VM_PROT_EXECUTE|VM_PROT_STRIP_READ)
164 
165 #ifdef PRIVATE
166 /*
167  * When using VM_PROT_COPY, fail instead of copying an executable mapping,
168  * since that could cause code-signing violations.
169  */
170 #define VM_PROT_COPY_FAIL_IF_EXECUTABLE ((vm_prot_t)0x100)
171 #endif /* PRIVATE */
172 
173 /*
174  * Another invalid protection value to support pager TPRO protection.
175  * VM_PROT_TPRO is a special marker that tells the a pager to
176  * set TPRO flags on a given entry. We do it this way to prevent
177  * bloating the pager structures and it allows dyld to pass through
178  * this flag in lieue of specifying explicit VM flags, allowing us to handle
179  * the final permissions internally.
180  */
181 #define VM_PROT_TPRO                    ((vm_prot_t) 0x200)
182 
183 #if defined(__x86_64__)
184 /*
185  * Another invalid protection value to support specifying different
186  * execute permissions for user- and supervisor- modes.  When
187  * MBE is enabled in a VM, VM_PROT_EXECUTE is used to indicate
188  * supervisor-mode execute permission, and VM_PROT_UEXEC specifies
189  * user-mode execute permission.  Currently only used by the
190  * x86 Hypervisor kext.
191  */
192 #define VM_PROT_UEXEC                   ((vm_prot_t) 0x8)     /* User-mode Execute Permission */
193 
194 #define VM_PROT_ALLEXEC                 (VM_PROT_EXECUTE | VM_PROT_UEXEC)
195 #else
196 #define VM_PROT_ALLEXEC                 (VM_PROT_EXECUTE)
197 #endif /* defined(__x86_64__) */
198 
199 
200 #endif  /* _MACH_VM_PROT_H_ */
201